In early days of flat panel display, technological innovation was driven by several trends such as image quality, screen size, portability and form factor. More recently, new drivers in flat panel display technology are product differentiation, flexibility, 3 D, transparency, system-on-panel, power savings, interconnectivity and screen size, and new front plane technologies. These new functional needs are beyond the performance limits of many existing technologies, requiring alternative solutions.
The backplane technology largely sets the limits of display industry. The backplane, consisting of thin film transistors (“TFTs”) that act as pixel switches, is responsible for turning the individual pixels ON and OFF. There are already many different mature and available, even fast-emerging, thin film transistors, including amorphous silicon, nanocrystalline silicon, low temperature polysilicon, solution processed or thermal evaporated organic semiconductor, various metal oxide, and the like.
Yet, none of current TFTs offers a one-technology-fits-all-needs solution, because each of the existing platforms has a different set of characteristics suitable for different applications.
Printing electronic components on flexible substrate with liquid inks is an attractive approach for achieving flexible and low-cost circuitry for applications such as bendable displays. Semiconductor-enriched single-walled carbon nanotubes (SWNTs) have been used to fabricate thin-film transistors on mechanically flexible substrates; however the methodology did not produce fully printed TFTs suitable for use in display backplanes. Methods and devices using fully integrated printing technology are desired.